The feedstuffs used in huge quantities in animal husbandry always contain biologically active substances which are sensitive to oxidation. These substances are generally stabilized by antioxidants, which should be devoid of any injurious effect to the living organism in the effective concentration and should be discharged rapidly, without leaving behind any residue.
It is well known that certain 1,2-dihydro-quinoline derivatives have valuable antioxidizing properties. The preferred representatives of these compounds are for example disclosed in the Hungarian Pat. Nos. 149,469; 157,370; 161,563 and 162,358; in the South-African Pat. No. 712,702 and in the Japanese Pat. Nos. 70,48--11,103.
The commercially available 1,2-dihydroquinoline antioxidants are dark colored, not uniform, viscous or amorphous substances. Due to their good solubility in lipoids and poor water-solubility these compounds can be accumulated in the fatty tissues of the animal organism and may cause the discoloration thereof.